1. Field Of The Invention
The present invention relates generally to tools for greasing vehicle wheel bearings and more particularly to an applicator for rapidly and efficiently delivering grease to bearings without the necessity of removing the wheel-retaining hardware, nor of raising the wheel off the ground.
2. Description Of The Related Art
Two wheels of the great majority of present day motor vehicles are mounted on non-rotating axles called 37 spindles." The wheel hub is mounted for rotation around the spindle by means of a pair of bearing sets, each set comprising a plurality of either rollers or balls. The bearing sets run between inner and outer races, the inner being fitted snugly on the spindle, the outer being fitted snugly in the bore of the wheel hub.
Each bearing set pair comprises an inboard bearing set which provides support for the hub on the end of the spindle proximal to the vehicle, and an outboard bearing set which supports the hub nearest the spindle's distal end. Each spindle, has means at its distal end for accommodating wheel-bearing bearing retaining hardware. This hardware commonly comprises a bearing-retaining washer and an adjusting nut which engages threads at the distal end of said spindle. A cotter pin through the spindle end prevents loosening of the nut.
The bearing sets of such spindle-mounted wheels require periodic regreasing both to reduce friction and to prevent dirty and gritty grease from damaging the bearings. This labor-intensive process first requires removal of the wheel and tire, and then the grease cap. Then the cotter pin, nut and washer are removed from the spindle, after which the bearing sets may be taken from their races and greased. If the wheel's brakes are of the disc-type, the caliper and rotor present additional obstacles in this task.
After the bearings have been cleaned and re-greased they are re-installed along with the hub on the spindle. One then replaces the washer and adjusts the bearing play by rotating the hub and tightening the nut to that optimum position in which it neither vibrates nor binds. Following this, the cotter pin and grease cap are installed. Only then may the wheel and tire be mounted on the hub because, if mounted before adjusting the bearing, the weight of the wheel and tire interfere with proper bearing adjustment. Thus, considerable effort must be expended merely to remove the bearings, and then to replace them after cleaning and re-greasing.
The cleaning and re-greasing process is itself a dirty, messy job and may also be labor-intensive. Traditionally, one simply held each bearing set in the palm of the hand and pressed clean grease into it until all the old grease was forced out. To avoid this, several devices have been developed to apply the grease in a cleaner, more effective manner. Examples of such devices can be found in U.S Pat. No. 2,866,520 issued to Sharp in 1957, and U.S. Pat. Nos. 4,355,702 and 4,405,035 issued to Shultz in 1982 and 1983, respectively. Each offers a mechanism for urging clean grease into a bearing set. Although these devices eliminate some unpleasant handling of bearings during the cleaning and re-greasing process, their use fails to eliminate the need to remove the wheel-retaining hardware for access to the bearings.
U.S. Pat. No. 4,293,056 issued to Setree in 1981 discloses a grease applicator which must be inserted through the bore of the hub while the bearings are in place and therefore requires removal of the hub from the spindle.
The prior art also includes devices for re-greasing wheel bearings without the removal of the wheel hub from the spindle. One such prior art grease applicator is shown in U.S. Pat. No. 2,514,799 issued to Rubertino, et al. in 1950. That device includes a disc-shaped member having a central aperture which receives the wheel's spindle after the wheel-retaining hardware has been removed. Rubertino's disk-shaped member is provided with a grease fitting and channels for directing grease to the wheel's outboard bearings.
Rubertino's device is inefficient in that the wheel-retaining hardware must be removed and replaced to permit its use. Whenever an adjusting nut is disturbed, the bearing play must be readjusted; therefore, Rubertino's device cannot be used without removal of the wheel and tire as well. Thus, the vehicle's wheel must be raised off the ground. None of these problems arise in using the present invention.
U.S. Pat. No. 4,190,133 issued to Ploeger in 1980 and U.S. Pat. No. 4,106,816 issued to August in 1978 show grease applicators which are designed to remain in place on the wheel hub during normal operation of the vehicle. Both include grease fittings and spring-loaded pistons for continuously urging grease toward the bearing. These devices are intended for use on boat trailers where bearings endure high-speed, high-temperature use followed by immersion in cold water. Upon inspection, it is apparent that either Ploeger's device or August's device could be installed temporarily to re-grease a wheel's bearings on a periodic basis with the wheel in place. However, neither device offers means for avoiding wasteful loading of grease upon the spindle end and nut. Neither are these devices able to deliver a discreet annular charge of grease directly into the bearing set of the wheel.
Chivukula, et al in U.S. Pat. No. 3,903,992 issued in 1975 shows a device for greasing the bearings of such a rotating shaft as may be found in an electric motor. Chivukula's device has grease inlet and outlet ports on opposite sides of the bearing. Grease is made to flow from one to the other by means of a grease slinger plate mounted on the shaft, said plate having canted vanes. Such a device could not be used to re-grease vehicle bearings since it is impossible or impractical to inject new grease behind a wheel bearing while mounted in the wheel and further, a stationary spindle could not drive a slinger plate to promote grease flow.